1 | # -*- coding: UTF-8 -*- |
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2 | # |
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3 | # PyKota : Print Quotas for CUPS |
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4 | # |
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5 | # (c) 2003, 2004, 2005, 2006, 2007, 2008 Jerome Alet <alet@librelogiciel.com> |
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6 | # This program is free software: you can redistribute it and/or modify |
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7 | # it under the terms of the GNU General Public License as published by |
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8 | # the Free Software Foundation, either version 3 of the License, or |
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9 | # (at your option) any later version. |
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10 | # |
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11 | # This program is distributed in the hope that it will be useful, |
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12 | # but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 | # GNU General Public License for more details. |
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15 | # |
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16 | # You should have received a copy of the GNU General Public License |
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17 | # along with this program. If not, see <http://www.gnu.org/licenses/>. |
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18 | # |
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19 | # $Id$ |
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20 | # |
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21 | # |
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22 | |
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23 | """This module defines a class to access to a PostgreSQL database backend.""" |
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24 | |
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25 | import time |
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26 | from types import StringType |
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27 | |
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28 | from pykota.errors import PyKotaStorageError |
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29 | from pykota.storage import BaseStorage |
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30 | from pykota.storages.sql import SQLStorage |
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31 | |
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32 | try : |
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33 | import pg |
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34 | except ImportError : |
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35 | import sys |
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36 | # TODO : to translate or not to translate ? |
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37 | raise PyKotaStorageError, "This python version (%s) doesn't seem to have the PygreSQL module installed correctly." % sys.version.split()[0] |
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38 | else : |
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39 | try : |
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40 | PGError = pg.Error |
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41 | except AttributeError : |
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42 | PGError = pg.error |
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43 | |
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44 | class Storage(BaseStorage, SQLStorage) : |
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45 | def __init__(self, pykotatool, host, dbname, user, passwd) : |
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46 | """Opens the PostgreSQL database connection.""" |
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47 | BaseStorage.__init__(self, pykotatool) |
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48 | try : |
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49 | (host, port) = host.split(":") |
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50 | port = int(port) |
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51 | except ValueError : |
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52 | port = 5432 # Use PostgreSQL's default tcp/ip port (5432). |
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53 | |
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54 | self.tool.logdebug("Trying to open database (host=%s, port=%s, dbname=%s, user=%s)..." % (host, port, dbname, user)) |
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55 | try : |
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56 | self.database = pg.connect(host=host, port=port, dbname=dbname, user=user, passwd=passwd) |
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57 | except PGError, msg : |
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58 | msg = "%(msg)s --- the most probable cause of your problem is that PostgreSQL is down, or doesn't accept incoming connections because you didn't configure it as explained in PyKota's documentation." % locals() |
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59 | raise PGError, msg |
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60 | self.closed = 0 |
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61 | try : |
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62 | self.database.query("SET CLIENT_ENCODING TO 'UTF-8';") |
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63 | except PGError, msg : |
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64 | self.tool.logdebug("Impossible to set database client encoding to UTF-8 : %s" % msg) |
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65 | self.tool.logdebug("Database opened (host=%s, port=%s, dbname=%s, user=%s)" % (host, port, dbname, user)) |
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66 | |
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67 | def close(self) : |
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68 | """Closes the database connection.""" |
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69 | if not self.closed : |
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70 | self.database.close() |
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71 | self.closed = 1 |
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72 | self.tool.logdebug("Database closed.") |
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73 | |
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74 | def beginTransaction(self) : |
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75 | """Starts a transaction.""" |
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76 | self.before = time.time() |
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77 | self.database.query("BEGIN;") |
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78 | self.tool.logdebug("Transaction begins...") |
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79 | |
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80 | def commitTransaction(self) : |
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81 | """Commits a transaction.""" |
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82 | self.database.query("COMMIT;") |
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83 | after = time.time() |
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84 | self.tool.logdebug("Transaction committed.") |
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85 | #self.tool.logdebug("Transaction duration : %.4f seconds" % (after - self.before)) |
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86 | |
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87 | def rollbackTransaction(self) : |
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88 | """Rollbacks a transaction.""" |
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89 | self.database.query("ROLLBACK;") |
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90 | after = time.time() |
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91 | self.tool.logdebug("Transaction aborted.") |
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92 | #self.tool.logdebug("Transaction duration : %.4f seconds" % (after - self.before)) |
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93 | |
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94 | def doRawSearch(self, query) : |
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95 | """Does a raw search query.""" |
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96 | query = query.strip() |
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97 | if not query.endswith(';') : |
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98 | query += ';' |
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99 | try : |
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100 | before = time.time() |
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101 | self.tool.logdebug("QUERY : %s" % query) |
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102 | result = self.database.query(query) |
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103 | except PGError, msg : |
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104 | raise PyKotaStorageError, str(msg) |
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105 | else : |
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106 | after = time.time() |
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107 | #self.tool.logdebug("Query Duration : %.4f seconds" % (after - before)) |
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108 | return result |
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109 | |
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110 | def doSearch(self, query) : |
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111 | """Does a search query.""" |
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112 | result = self.doRawSearch(query) |
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113 | if (result is not None) and (result.ntuples() > 0) : |
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114 | return result.dictresult() |
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115 | |
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116 | def doModify(self, query) : |
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117 | """Does a (possibly multiple) modify query.""" |
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118 | query = query.strip() |
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119 | if not query.endswith(';') : |
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120 | query += ';' |
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121 | try : |
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122 | before = time.time() |
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123 | self.tool.logdebug("QUERY : %s" % query) |
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124 | result = self.database.query(query) |
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125 | except PGError, msg : |
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126 | self.tool.logdebug("Query failed : %s" % repr(msg)) |
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127 | raise PyKotaStorageError, str(msg) |
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128 | else : |
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129 | after = time.time() |
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130 | #self.tool.logdebug("Query Duration : %.4f seconds" % (after - before)) |
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131 | return result |
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132 | |
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133 | def doQuote(self, field) : |
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134 | """Quotes a field for use as a string in SQL queries.""" |
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135 | if type(field) == type(0.0) : |
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136 | typ = "decimal" |
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137 | elif type(field) == type(0) : |
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138 | typ = "int" |
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139 | elif type(field) == type(0L) : |
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140 | typ = "int" |
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141 | else : |
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142 | typ = "text" |
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143 | return pg._quote(field, typ) |
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144 | |
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145 | def prepareRawResult(self, result) : |
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146 | """Prepares a raw result by including the headers.""" |
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147 | if result.ntuples() > 0 : |
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148 | entries = [result.listfields()] |
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149 | entries.extend(result.getresult()) |
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150 | nbfields = len(entries[0]) |
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151 | for i in range(1, len(entries)) : |
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152 | fields = list(entries[i]) |
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153 | for j in range(nbfields) : |
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154 | field = fields[j] |
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155 | if type(field) == StringType : |
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156 | fields[j] = self.databaseToUserCharset(field) |
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157 | entries[i] = tuple(fields) |
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158 | return entries |
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159 | |
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